Trans-septal catherization procedures typically involve insertion of a needle, such as the trans-septal needle of Cook Incorporated (Bloomington, Ind., USA) into a patient's heart. The needle comprises a stiff metal cannula with a sharpened distal tip. The needle is generally introduced through a dilator and guiding sheath set in the femoral vein and advanced through the vasculature into the right atrium. From there the needle tip is positioned at the fossa ovalis, the preferred location on the septum for creating a puncture. Using a needle trans-septal puncture is complicated by the necessity of accessing the heart through the femoral vein and inferior vena cava. Occasionally, due to abnormalities of the venous system such as azygous continuation of the inferior vena cava or thrombosis or obliteration of the iliofemoral veins it may not be possible to gain access to the right atrium using a femoral approach. In addition, the standard femoral transvenous approach to the atrial septum for trans-septal access, as described earlier, may be difficult in situation where the cardiac anatomy is grossly distorted such as in patients with longstanding and marked elevation of left atrial and pulmonary artery pressures, or patients who have previously undergone cardiac surgery. Gaining trans-septal access from the femoral approach may also be difficult in patients with dextrocardia, a condition in which the heart is located on the right side of the chest rather than the left and in whom there is significant variation in the orientation of the atrial septum.
A trans-jugular approach, using a needle to gain trans-septal access, is described by Joseph et. al. (1997). Joseph states that trans-jugular septal puncture may find application in cardiac electrophysiology because it offers a more direct approach to the mitral annulus, left ventricle, and inferior aspect of the left atrium. In another publication by Joseph et. al. (2000), the author states that in transvenous mitral valvuloplasty, the jugular approach simplifies septal puncture and mitral valve crossing in patients with a huge left atrium and distorted anatomy, besides making the procedure feasible in the presence of obstruction of the inferior vena cava. However, needle trans-septal punctures from the jugular approach are more difficult to perform and require significant practice. Cheng (2003), commenting on the aforementioned articles, states that the transjugular approach for trans-septal needle puncture is more difficult to perform than the transfemoral approach and that only with larger studies and more experience will we be able to tell whether the innovative tranjugular approach is as versatile, efficacious, and safe as the conventional transfemoral approach.
U.S. Pat. No. 6,565,562 to Shah et al., entitled “Method for the radio frequency perforation and the enlargement of a body tissue” issued May 20, 2003, describes a method of perforating tissue using a radiofrequency (RF) perforating device. A functional tip on the RF perforating device is placed against target tissue and as RF current is applied a perforation is created. This method allows the RF perforating device to easily pass through the tissue without applying significant force that could cause the tissue to tent. However, Shah et al. do not describe employing such a device using a non-femoral approach to perforate bodily tissue, which would require a means of positioning the perforation device appropriately to allow for perforation and/or dilation.
The SafeSheath® CSG Worley, described in the publication entitled “Using the Pressure Products SafeSheath CSG Worley with Radio Opaque Soft-Tipped Braided Core” is a surgical sheath designed to be introduced into a patient's heart through the Superior Vena Cava (SVC) and on through the coronary sinus. The SafeSheath® device is not intended or structured to allow for perforation of patient material nor is it structured to allow for positioning within a patient's heart for perforation and/or dilation.
Thus, patients requiring trans-septal punctures would benefit from a device that utilizes a non-femoral, i.e. superior, approach and which is more reliable and user-friendly than the trans-septal needle. In particular, the patient population discussed above would benefit from a device and technique for trans-septal perforation that allows for a multiplicity of uncomplicated intravascular approaches as well as providing a more controlled method of perforation.